Preparation Of Graphene By Micro Jet Homogenization

With the continuous breakthrough of graphene key technology and the maturity of downstream application framework,and its excellent characteristics,it will replace partially Indium Tin Oxide(ITO),traditional capacitor and lithium battery materials in the future,which brings huge market demand and production capacity requirements for graphene industry.At present,the mass-produced graphene is mainly prepared by oxidation-reduction method,liquid phase stripping method and chemical vapor deposition method.Among them,the liquid phase stripping method can solve the problems of insufficient yield,high cost and so on.At the same time,it has little environmental pollution,and does not involve the problems of waste liquid pollution caused by oxidation.It is suitable for industrial production and has attracted much attention.In this paper,the industrial production of conductive graphene is taken as the goal,and the micro jet homogenization method in liquid phase stripping is used to peel the graphite micro sheet.The processing flow of different graphite micro sheet dispersions is studied,and the main process parameters such as homogenization pressure,slurry size and configuration concentration are optimized.Then,the effect of adding carbon black to the graphite micro sheet dispersions on improving the conductivity of graphene is verified.The main results are as followsExpanded graphite and flake graphite were added into 20%NMP(N-Methylpyrrolidone)aqueous solution and 20%DMF(N,N-Dimethylformamide)aqueous solution to obtain graphene by shearing,ultrasonic pretreatment and micro jet homogenization,respectively.The process parameters of industrial production were optimized by adjusting homogenization pressure,slurry size and dispersion concentration.The results show that the particle size of 20%NMP dispersion prepared with 1.5 wt%graphite microchip is refined to 7μm after homogenization at 80 MPa.The yield of graphene is 97.4%.At 12 MPa,the conductivity is 560 S/cm,and the Raman spectrum I_D/I_G is 0.24.A method of preparing graphene with carbon black was developed.Expanded graphite,flake graphite and high conductivity carbon black were added into 20%NMP aqueous solution,homogenized with 80 MPa homogenization pressure,and the D50 particle size was controlled to 6.5μm,after spray drying and powder making,was observed at SEM.It is possible to prevent the stacking of graphene sheets.At 12 MPa,the conductivity is 646.35 S/cm,and the Raman spectrum I_D/I_G=0.21.In general,because a small amount of carbon black is added,the conductivity of graphene is increased,and the particle size is smaller after homogenization under the same process parameters,which has a certain significance for industrial production.